nested-fragments | nested fragments in various widgets | Android library

Hello good programmers of stack overflow! I've spent a good week with this problem and am now very desperate for a solution.

I'm using android.app.Fragment's not to be confused with the support fragments.

I have 6 child fragments named:

• FragmentOne
• FragmentTwo
• FragmentThree
• FragmentA
• FragmentB
• FragmentC

I have 2 parent fragments named:

• FragmentNumeric
• FragmentAlpha

I have 1 activity named:

• MainActivity

They behave in the following:

• Child fragments are fragments that only show a view, they do not show nor contain fragments.
• Parent fragments fill their entire view with a single child fragment. They're able to replace the child fragment with other child fragments.
• The activity fills most of its view with a parent fragment. It can replace it with other parent fragments. So at any one time the screen has just a single child fragment showing.

As you've probably guessed,

FragmentNumeric shows child fragments FragmentOne, FragmentTwo, and FragmentThree.

FragmentAlpha shows child fragments FragmentA, FragmentB, and FragmentC.

I'm trying to transition/animate parent and child fragments. The child fragments transition smoothly and as expected. However when I transition to a new parent fragment, it looks terrible. The child fragment looks like it runs an independent transition from its parent fragment. And the child fragment looks like it is removed from the parent fragment as well. A gif of it can be viewed here https://imgur.com/kOAotvk. Notice what happens when I click Show Alpha.

The closest question & answers I could find are here: Nested fragments disappear during transition animation however all of the answers are unsatisfying hacks.

I have the following animator effects (duration is long for testing purposes):

fragment_enter.xml